// SPDX-License-Identifier: GPL-2.0-or-later/* * * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) */#include <linux/types.h>#include <linux/slab.h>#include <linux/socket.h>#include <linux/timer.h>#include <net/ax25.h>#include <linux/skbuff.h>#include <net/rose.h>#include <linux/init.h> static struct sk_buff_head loopback_queue;#define ROSE_LOOPBACK_LIMIT 1000static struct timer_list loopback_timer; static void rose_set_loopback_timer(void);static void rose_loopback_timer(struct timer_list *unused); void rose_loopback_init(void){	skb_queue_head_init(&loopback_queue); 	timer_setup(&loopback_timer, rose_loopback_timer, 0);} static int rose_loopback_running(void){	return timer_pending(&loopback_timer);} int rose_loopback_queue(struct sk_buff *skb, struct rose_neigh *neigh){	struct sk_buff *skbn = NULL; 	if (skb_queue_len(&loopback_queue) < ROSE_LOOPBACK_LIMIT)		skbn = skb_clone(skb, GFP_ATOMIC); 	if (skbn) {		consume_skb(skb);		skb_queue_tail(&loopback_queue, skbn); 		if (!rose_loopback_running())			rose_set_loopback_timer();	} else {		kfree_skb(skb);	} 	return 1;} static void rose_set_loopback_timer(void){	mod_timer(&loopback_timer, jiffies + 10);} static void rose_loopback_timer(struct timer_list *unused){	struct sk_buff *skb;	struct net_device *dev;	rose_address *dest;	struct sock *sk;	unsigned short frametype;	unsigned int lci_i, lci_o;	int count; 	for (count = 0; count < ROSE_LOOPBACK_LIMIT; count++) {		skb = skb_dequeue(&loopback_queue);		if (!skb)			return;		if (skb->len < ROSE_MIN_LEN) {			kfree_skb(skb);			continue;		}		lci_i     = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);		frametype = skb->data[2];		if (frametype == ROSE_CALL_REQUEST &&		    (skb->len <= ROSE_CALL_REQ_FACILITIES_OFF ||		     skb->data[ROSE_CALL_REQ_ADDR_LEN_OFF] !=		     ROSE_CALL_REQ_ADDR_LEN_VAL)) {			kfree_skb(skb);			continue;		}		dest      = (rose_address *)(skb->data + ROSE_CALL_REQ_DEST_ADDR_OFF);		lci_o     = ROSE_DEFAULT_MAXVC + 1 - lci_i; 		skb_reset_transport_header(skb); 		sk = rose_find_socket(lci_o, rose_loopback_neigh);		if (sk) {			if (rose_process_rx_frame(sk, skb) == 0)				kfree_skb(skb);			continue;		} 		if (frametype == ROSE_CALL_REQUEST) {			if ((dev = rose_dev_get(dest)) != NULL) {				if (rose_rx_call_request(skb, dev, rose_loopback_neigh, lci_o) == 0)					kfree_skb(skb);			} else {				kfree_skb(skb);			}		} else {			kfree_skb(skb);		}	}	if (!skb_queue_empty(&loopback_queue))		mod_timer(&loopback_timer, jiffies + 1);} void __exit rose_loopback_clear(void){	struct sk_buff *skb; 	del_timer(&loopback_timer); 	while ((skb = skb_dequeue(&loopback_queue)) != NULL) {		skb->sk = NULL;		kfree_skb(skb);	}}